The present embodiments relate to ultrasound transducers. In particular, a method of manufacture of backing is provided.
One-dimensional arrays of transducers connect with system channels by flex material. The flex material is aligned with elements of the array. Behind the elements and the flex is acoustic backing material. The acoustic backing material attenuates acoustic energy, limiting reflection of signals not from the tissue being scanned. The flex material is thin enough to avoid reflections.
For two-dimensional arrays, flex material may not provide sufficient conductor density. Alternatives have been proposed, such as z-axis conductors. The acoustic backing is formed with conductors extending along the range dimension through the backing material. However, alignment and holding of these conductors during formation of the backing material may be difficult. The density of the wires on the back of the backing material is still high, resulting in difficulty for connection.
A further problem is the number of cables to the ultrasound imaging system. To limit the number of cables, circuits are positioned in the ultrasound probe housing. The circuits connect with the elements, such as with z-axis conductors in the backing. The circuits combine signals from a plurality of elements, such as through partial beamforming or multiplexing. The combination reduces the number of cables needed to the imaging system. However, the interconnection of the electrodes of the elements to the circuitry may be difficult.
Each element of an array connects with two conductive paths. The conductive paths may include connections to circuits within a probe, connections from the circuits to the cable, and connections from the cable to beamformers in the imaging system. There may be thousands of interconnections within the circuits, thousands more for element-to-flex, thousands more for flex-to-circuit, and more from circuit-to-cable interconnections. The number of connections may be large, resulting in increased parasitics, increased chance of shorting, and required expensive manufacturing.